请教：电子衍射可以研究2-3nm的纳米粒子么？ - 未名空间MITBBS历史存档

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请教：电子衍射可以研究2-3nm的纳米粒子么？

请教：电子衍射可以研究2-3nm的纳米粒子么？# Chemistry - 化学

c*i2012-05-18 07:05

1 楼

Amy Chang-Chien Hsueh, Taiwan: Fresh Deciduous Fruit Annual (report).
Foreign Agricultural Service, US Department of Agriculture. Dec.18, 2009.
http://gain.fas.usda.gov/Recent%20GAIN%20Publications/FRESH%20DECIDUOUS%20FRUIT%20ANNUAL_Taipei_Taiwan_12-18-2009.pdf
Quote:
"The apple is, far and away, the most heavily consumed imported fruit in
Taiwan. [Note the word "import," for this excludes locally grown oranges;
see below] Fuji, with its sweet taste and firm texture, remains the
overwhelmingly

h*n2012-05-18 07:05

2 楼

假如大使馆这边发NOL比较晚了，比如J1到期，而人也已经离开美国。
这样的话美国DOS在收到NOL后还会继续完成豁免流程吗？

j*d2012-05-18 07:05

3 楼

夫妻两都是14年下半年转OPT工作，09年来美，应该已是resident alien
现两人都收到学校和公司的W2，学校的1042-S，还有炒股一小部分收入，都是在一个州
请问这种情况用什么保税软件比较方便，学校提供了一种叫sprintax的，不知道是不是
功能有限，退税额也会受影响
如果买turbotax之类的，如果联合报税是不是只需要买一份就可以了
谢谢

S*n2012-05-18 07:05

4 楼

多谢讨论，包子酬谢！

s*u2012-05-18 07:05

5 楼

DOS在收到NOL后还会继续完成豁免流程

【在 h*****n 的大作中提到】

: 假如大使馆这边发NOL比较晚了，比如J1到期，而人也已经离开美国。
: 这样的话美国DOS在收到NOL后还会继续完成豁免流程吗？

M*s2012-05-18 07:05

6 楼

买turbotax的话，联合报税一份就可以

b*g2012-05-18 07:05

7 楼

X-ray should work, there is a Science paper in 2009(?)

S*n2012-05-18 07:05

8 楼

I wish I could do XRD, but your boss asked me to do ED...

【在 b*******g 的大作中提到】

: X-ray should work, there is a Science paper in 2009(?)

z*r2012-05-18 07:05

9 楼

看是什么材料，结构稳定的氧化物应该还可以，金属颗粒这么小应该不行，在电子束轰
击下会结构重组。

S*n2012-05-18 07:05

10 楼

metal np with core-shell structure...the reviewer is crazy...
could you please provide a reference?

【在 z****r 的大作中提到】

: 看是什么材料，结构稳定的氧化物应该还可以，金属颗粒这么小应该不行，在电子束轰
: 击下会结构重组。

S*n2012-05-18 07:05

11 楼

J. Phys. Chem. B 2003, 107, 7351-7354
The reviewer asked me to follow this paper.
But it seems to me that in this paper they did not do real diffraction. The
(111) patterns are just from an image processing software. Am I right?

【在 z****r 的大作中提到】

: 看是什么材料，结构稳定的氧化物应该还可以，金属颗粒这么小应该不行，在电子束轰
: 击下会结构重组。

m*c2012-05-18 07:05

12 楼

are you claiming a core-shell structure of 2-3 nm particle?

【在 S*****n 的大作中提到】

: metal np with core-shell structure...the reviewer is crazy...
: could you please provide a reference?

S*n2012-05-18 07:05

13 楼

yes

【在 m***c 的大作中提到】

: are you claiming a core-shell structure of 2-3 nm particle?

f*n2012-05-18 07:05

14 楼

如果光是分析晶面的话, 没有必要做衍射啊，直接 HRTEM，然后 FFT 转换一下也能得
到点阵啊。

【在 S*****n 的大作中提到】

: 多谢讨论，包子酬谢！

z*r2012-05-18 07:05

15 楼

看了一下文章，不太清楚是不是FFT，但应该不是ED。整个core-shell结构加起来2-3nm
的话，做ED也不是完全不可以，但可能对仪器要求很高。如果想验证core-shell，尝试
一下EDX或者EELS的线扫描？

The

【在 S*****n 的大作中提到】

: J. Phys. Chem. B 2003, 107, 7351-7354
: The reviewer asked me to follow this paper.
: But it seems to me that in this paper they did not do real diffraction. The
: (111) patterns are just from an image processing software. Am I right?

z*r2012-05-18 07:05

16 楼

I have no relevant references in my hand. It is based on my own experience.
I once used one utra HRTEM with a 0.5 A spatial resolution to characterize 2
nm Pt particles. I directly saw surface atoms moving around and even
restruction of crystal structures. You may check papers published by
Christian Kisielowski at LBL. He may publish some papers on this topic.

【在 S*****n 的大作中提到】

: metal np with core-shell structure...the reviewer is crazy...
: could you please provide a reference?

m*c2012-05-18 07:05

17 楼

hard to show by ED. only 4-5 unit cells overall, if it is core-shell, 2-3
unit cells for each phase. dont' know how it would scatter the electrons.

【在 S*****n 的大作中提到】

: yes

S*n2012-05-18 07:05

18 楼

OK
reviewer asked me to do that
I will just say no
thanks for all discussions

【在 m***c 的大作中提到】

: hard to show by ED. only 4-5 unit cells overall, if it is core-shell, 2-3
: unit cells for each phase. dont' know how it would scatter the electrons.

g*e2012-05-18 07:05

19 楼

It may be hard but in principle it is feasible. Even a single layer of atoms
scatter electrons. In my opinion 2-3 nm is perfect for electron diffraction
since there are no dynamical effects.

【在 m***c 的大作中提到】

: hard to show by ED. only 4-5 unit cells overall, if it is core-shell, 2-3
: unit cells for each phase. dont' know how it would scatter the electrons.